1. Field of the Invention:
This invention relates to a plastic surface fastener consisting of two surface fastener members each comprising a flat plastic base and multiple projecting members having identically sized engagement heads and provided to stand upright on the base, which surface fastener members can be engaged by pressing them on to each other and disengaged by stripping them apart.
2. Description of the Prior Art:
Recent years have seen an increase in the number of applications for press-on-strip-off plastic surface fasteners. Such fasteners have come into wide use in the automotive sector, for example, where they are utilized for such purposes as attaching various passenger compartment finishing materials, preventing head lining sag, and holding down glass members.
A prior art plastic surface fastener of this type is described in U.S. Pat. No. 5,212,853, for example. The surface fastener taught by this patent consists of two surface fastener members each constituted of a plastic base and multiple projecting members having identically sized engagement heads and provided to stand upright on the base. Each of the engaging heads is integrally supported on the associated base by two legs whose distal ends are attached to the engaging head at opposing positions on the periphery of the bottom surface thereof.
As shown in the side view of this prior art surface fastener in FIG. 7(a), the surface fastener 1 consists of two surface fastener members A and B of identical structure. Specifically, each surface fastener member has a base 20 and numerous projecting members 21 standing upright on the base 20, and each of the projecting members 21 consists of a hemispherical engaging head 22 and two legs 23 extending perpendicular to the base 20 for integrally connecting the engaging head 22 with the base 20.
Viewed from above, the projecting members 21 are arranged on the base 20 in the form of a matrix of regular pitch. As shown in FIG. 7(b), the spacing between adjacent projecting members 21 is such that when a projecting member 21A of one surface fastener member A is forced into the space enclosed by four engaging heads 22B of the other surface fastener member B, the upward facing engaging head 22A of the surface fastener member A is caught by each of the four engaging heads 22B.
For realizing the aforesaid arrangement of the prior art surface fastener, the projecting members 21 have to be arranged densely with their engaging heads 22 nearly in contact with each other in both the surface fastener member A and the surface fastener member B. Therefore, as shown in FIG. 7(b), when the engaging heads 22A of projecting members 21A of the surface fastener member A are forced into each of the spaces enclosed by four engaging heads 22B of the other surface fastener member B, the engaging heads 22A and the engaging heads 22B get in each other's way so that the four projecting members 21B of the surface fastener member B have no or only little room to escape outward from the center of the invading projecting members 21A. As a result, a large force is required for pressing the surface fastener into engagement.
An object of this invention is to provide a plastic surface fastener which requires less force to press it into engagement.